Coloring paper and the like



Patented Sept. 5, 1933 COLORING PAPER AND THE LIKE Franz Dotzel,Ludwigshafen-on-the-Rhine, Germany, assignor to I. G. FarbenindustrieAktiengesellschaft, FrankIort-on-the-Main, Germany N Drawing.

Application September 24, 1930,

Serial No. 484,245, and in Germany October 12 Claims.

stuffs. The phenomenon is therefore particular-- ly marked with the useof paper from mixed paper pulp. It has been tried to avoid thisdisagreeable eifect by a-treatment with tannin, but the results are notsatisfactory.

I have now found that paper, which term is meant to include paper ofanysize, 1. e. thin paper as well as pasteboard and the like, can becolored in a manner free from the aforesaid objections with organicdyestuffs, such as basic, substantive and similar dyestuffs, and thattherefore very valuable uniformly colored paper and the like can beobtained by treating the substances serving for the preparation of thepaper and the like during the working up thereof, or by treating thepaper and the like themselves before, or at the same time as, coloringthem, with certain artificial tanning agents. After thorough mixing, thepulp is colored and sized in the usual manner. The artificial tanningagents suitable according to my present invention correspond to thegeneral formula R- X- R- in which R defines a monoor polycyclic aromaticnucleus, which may contain further non-aromatic substituents, and X isCH2, CHz-NH or S. Thus for example tanning compounds of the type (3H,/SO;H S\ l? .11, HO 0H 1 H or v soln I 802B Patents Nos. 297,187,297,188, 319,713 and 320,613

also describe the preparation of tanning mate rials suitable forcarrying out the present invention. Particularly good results areobtained with aromatic sulphonic acids corresponding to the lastmentioned formula and their efliciency may be further increased byconverting the acid tanning agents of the aforesaid nature into theiralkali metal salts and adding, if desired, from 0.5 to 5 per cent theirweight of alkali metal bisulphate. V

The quantities of the artificial tanning agents employed are generallybetween 0.2 and 5 per cent of .the paper pulp or paper, quantitiesbetween 0.5 and 1 per cent being usually satisfactory.

The good results obtainable according to the present invention are mostsurprising since tanning agents of unsymmetrical constitution, as forexample phenyl methylene naphthyl compounds, do not prevent thedisagreeable mottled effects.

The following examples, in which coloring with dyestuffs particularlytending to give mottled dyeings is described, will further illustratethe nature of this invention, but the invention is not restrictedthereto.

Example 1 From 0.5 to 1 per cent of the sodium salt of the synthetictanning agent, prepared by condensation of fl-naphthalene sulphonic acidand formaldehyde, and which has been dissolved in water, incorporatedwith from 1 to 3 per cent its weight of sodium bisulphate and renderedneutral, is added to the paper pulp in a hollander. The pulp is thencolored according to the desired shade, as for example with methyleneBlue (Color Index, No. 922) or Cotton black RW extra (Color Index, No.582) and sized in the usual manner. In the product obtained all fibresare equally dyed.

Example 2 1000 parts of a mixture of 7.5 parts of bleached sulphite pulpand 2.5 parts of unbleached sulphite pulp are worked in the papermachine together with 10 parts of the tanning agent, prepared by acondensation of phenol with sulphur and alkali, 500 parts of water and 5parts of the dyestuff Vesuvine B (Color Index, No. 332). Thoroughlyuniform dyeings are obtained.

Example 3' 1000 parts of a mixture of equal parts of mechanical pulp anaof unbleached sulphite pulp densation of B-naphthalene sulphonic acidand formaldehyde, and which has been dissolved in .water and renderedneutral, 500 parts of water and 2 parts of Cotton black RW extra (ColorIndex, No. 582). The dyed paper or pasteboard does not show any mottledefiects.

What I claim is:'- I

l. The process for coloring paper with an organic dyestuff selected fromthe class consisting of basic and substantive dyestuffs which comprisestreating paper pulp at least during the dyeing operation with asynthetic tanning agent containing the grouping (R- X- R-)y in which tis greater than 1, R is an aromatic nucleus and X is CH2, CH2NH or S.

2. The process for coloring paper with an organic dyestufi selected fromthe class consisting of basic and substantive dyestuffs whichcomprisestreating paper pulp at least during the dyeing operation with asynthetic tanning agent result- .ing from the condensation of anaphthalene sulphonic acid with formaldehyde.

3. The process for coloring paper with an organic dyestuff selected fromthe class consisting of basic and substantive dyestuifs which comprisestreating paper pulp at least during the dyeing operation with asynthetic tanning agent resulting from the condensation of a naphthalenesulphonic acid with formaldehyde, and subsequent neutralization.

4. As a new article of manufacture papercomprising a synthetic tanningagent containing the grouping (R- X- R-)y in which 1/ is greater than 1,R is an aromatic nucleus and X is CH2, CH2- NH or S, which is uniformlycolored by an organic dyestufi selected from the class consisting ofbasicand substantive dyestuffs.

5. As a new article of manufacture paper comprising a neutralizedsynthetic tanning agent containing the grouping (R- X: R011 in which 31is greater than 1, Ris an aromatic nucleus and X is CH2, CH2NH or S,which isuniformly colored by an organic dyestuif selected from the classconsisting of basic and substantive dyestuil's.

6. Asa newarticle of manufacture paper comprising a synthetic tanningagent resulting from ne ates;

tion for uniformly coloring paper, comprising a neutralized synthetictanning agent containing the grouping (R X- R011 in which 31 is greaterthan 1, R is an aromatic nucleusand X is CH2,

CHz-NH or S and a paper dyeing coloring material selected from the classconsisting of basic and substantive dyestuffs.

9. As a new'article of manufacture a preparation for uniformly coloringpaper, comprising a synthetic tanning agent resulting from thecondensation of a naphthalene sulphonic acid and formaldehyde-andsubsequent neutralization with an alkali and a paper dyeing coloringmaterial selected from the class consisting of basic and substantivedyestufi's.

10. A composition of matter comprising paper pulp, a synthetic tanningagent containing the grouping (R- X- Roy in which 1/ is greater than 1,R is an aromatic nucleus and X is CH1, CH2 NH or S, and an organicdyestufi selected from the class consisting of basic and substantivedyestuffs.

11. A composition of matter comprising paper pulp, a neutralizedsynthetic tanning agent resulting from the condensation of a naphthalenesulphonic acid and formaldehyde, and an organic dyestufl? selected fromthe class consisting of basic and substantive dyestufls.

12. A composition of matter comprising mechanical pulp and unbleachedsulphite pulp, the sodium salt of a synthetic tanning agent resultingfrom the condensation of beta-naphthalene sulphonic acid andformaldehyde, and an organic dyestuif selected from the class consistingof basic and substantive dyestufis. I

. FRANZ DOTZEL.

will

